raised by smmc in discourse:
It is possible to set a call destination of Feature Code Admin, Contact Manager Speeddials. But when the call goes to this destination it fails. I can see no practical purpose for being allowed to set this as a destination, and recommend that this option be removed.
It's possible that it was added for ticket
FREEPBX-8203, which was a request that individual contact manager entries be usable as a destination, but it's not working.